Optical pickup device and recording and/or reproducing device

ABSTRACT

This device has an optical pickup section, a first rack portion provided on the optical pickup section, a slide member having an opening/closing portion for opening/closing a facing surface of the objective lens to the optical disc and a second rack portion provided to be slidable on the first rack portion, and a driving mechanism having a driving gear which meshes with the first rack portion and the second rack portion. In this device, when the optical pickup section is moved to a predetermined position, the meshing state of the first rack portion with the driving gear is canceled and the second rack portion is driven by the driving gear to move the slide member, thereby moving the opening/closing portion from a position for opening the facing surface side of the objective lens to a position for closing the facing surface side.

TECHNICAL FIELD

[0001] This invention relates to an optical pickup device for recordingand/or reproducing information to and/or from a disc-shaped recordingmedium such as an optical disc or a magneto-optical disc, and arecording and/or reproducing device having this optical pickup device.

BACKGROUND ART

[0002] An optical pickup device which reproduces information from anoptical disc such as a CD (compact disc) as an optical disc is known.The optical pickup device of this type has an optical pickup 111 forreproducing information from an optical disc, a moving mechanism 112 formoving the optical pickup 111 in the radial direction of the opticaldisc, and a chassis 113 for movably supporting the optical pickup 111and also supporting the moving mechanism 112, as shown in FIG. 1.

[0003] The optical pickup 111 is provided movably in the directions ofarrows b1 and b2 in FIG. 1, in an aperture 116 for movement provided inthe chassis 113, as shown in FIG. 1. The optical pickup 111 has anoptical system (not shown) having an objective lens 118, a drivingportion (not shown) for driving and displacing the objective lens 118 inthe direction of the optical axis of the objective lens 118 and in thedirection orthogonal to the optical axis, and a cover member 120 forcovering the driving portion.

[0004] The optical pickup 111 has a light source such as a laser diodefor emitting a laser beam, a group of lenses constituting the opticalsystem, and a light receiving section for receiving a reflected lightfrom the optical disc, though not shown in the drawing. The drivingsection provided in the optical pickup 111 has a lens holder for holdingthe objective lens 118, a supporting mechanism for supporting the lensholder displaceably in the direction of the optical axis of theobjective lens 118 and in the direction orthogonal to the optical axis,and an electromagnetic circuit section for driving the lens holder by anelectromagnetic force. The cover member 120 is made of, for example, aresin material formed in a substantially box-like shape, and has asubstantially elliptic aperture 121 provided therein for exposing theobjective lens 118 to the optical disc, as shown in FIG. 1.

[0005] The moving mechanism 112 has a supporting base 123 for supportingthe optical pickup 111, a supporting shaft 124 for supporting thesupporting base 123 movably in the radial direction of the optical disc,a guide portion 125 for movably guiding the supporting base 123, a slidemember 126 for moving the supporting base 123, a compression coil spring127 for energizing the slide member 126 in the axial direction of thesupporting shaft 124 with respect to the supporting base 123, a drivinggear 128 for driving the slide member 126, and a driving motor, (notshown) for rotationally driving the driving gear 128, as shown in FIG.1.

[0006] The optical pickup 111 is arranged on the major surface of thesupporting base 123, and the supporting base 123 has bearing portions131, 131 through which the supporting shaft 124 is movably inserted anda guide recess portion 132 which is movably engaged with the guideportion 125, as shown in FIGS. 1 and 2. At one end of the supportingbase 123, a rack portion 133 which is meshed and moved with the drivinggear 128 is integrally formed.

[0007] This rack portion 133 is formed parallel to the axial directionof the supporting shaft 124, as shown in FIG. 1. The rack portion 133has engagement pawls 135, 135 which are engaged with the slide member126, and a retaining piece 136 for retaining one end of the compressioncoil spring 127.

[0008] As shown in FIG. 1, the axial direction of the supporting shaft124 is arranged parallel to the radial direction of the optical disc,across the aperture 116 for movement of the chassis 113, and both endsof the supporting shaft 124 are fixed on the chassis 113 by fixingportions, not shown.

[0009] The guide portion 125 is linearly formed by using a resinmaterial and is formed parallel to the axial direction of the supportingshaft 124 along one lateral edge of the aperture 116 for movement of thechassis 113, as shown in FIG. 1. With this guide portion 125, the guiderecess portion 132 of the supporting base 123 is movably engaged, asshown in FIG. 2.

[0010] The slide member 126 has a rack portion 138 formed parallel tothe axial direction of the supporting shaft 124, and this rack portion138 is shifted by approximately a half cog thickness from he rackportion 133 of the supporting case 123, as shown in FIG. 3. In the slidemember 126, engagement holes 140, 140 are formed which are engaged withthe engagement pawls 135, 135 of the rack portion 133 of the supportingbase 123, as shown in FIG. 1. Moreover, an aperture 141 in which thecompression coil spring 127 is arranged is provided substantially at thecenter of the major surface of the slide member 126, and a retainingpiece 142 for retaining the other end of the compression coil spring 127is formed at one end of the aperture 141.

[0011] As shown in FIG. 1, one end of the compression coil spring 127 isretained by the retaining piece 136 of the rack portion 133 of thesupporting base 123, and the other end of the compression coil spring127 is retained by the retaining piece 142 of the slide member 126.Therefore, the compression coil spring 127 energizes, by its elasticforce, the slide member 126 in the direction of an arrow b3 parallel tothe axial direction of the supporting shaft 124 with respect to the rackportion 133 of the supporting base 123.

[0012] In the optical pickup device, in order to prevent attachment ofdust and particles to the facing surface of objective lens 118 of theoptical pickup 111 which faces the optical disc due to an air currentwithin the device in the reproduction standby state or the like, anopening/closing mechanism 145 is provided which has an opening/closingmember 146 provided movably between a closing position for covering thefacing surface of the objective lens 118 and an opening position foropening and exposing the facing surface of the objective lens 118 to theoptical disc, as shown in FIG. 1.

[0013] The opening/closing mechanism 145 has the opening member 146 foropening/closing the facing surface of the objective lens 118, a rotaryshaft 147 for rotatably supporting the opening/closing member 146, and atension coil spring 148 for energizing the opening/closing member 146 tothe closing position, as shown in FIGS. 1 and 4.

[0014] As shown in FIG. 1, the opening/closing member 146 has anopening/closing portion 151 for opening/closing the aperture 121 of thecover member 120 of the optical pickup 111, a bearing portion 152 forrotatably supporting the rotary shaft 147, a guide portion 153 slidablyengaged with the cover member 120 for guiding the opening/closingportion 151, and an operating portion 154 for rotating theopening/closing portion 151 in the directions of arrows c1 and c2 inFIG. 1.

[0015] The opening/closing portion 151 is formed in a substantially flatplate-like shape and slides on the upper surface of the cover member120, thus opening/closing the aperture 121 of the cover member 120. Thebearing portion 152 is integrally formed at one end of theopening/closing portion 151 and has a shaft hole in which the rotaryshaft 147 is rotatably inserted. The guide portion 153 is formed to havea cross section of a substantially U-shape fallen sideways, and isslidably engaged with a substantially arc-shaped guide piece 155 whichis integrally formed to protrude on the outer circumferential portion ofthe cover member 120. The operating portion 154 is formed at a positionwhere it is exposed to an operating protrusion 156 provided on thechassis 113, on the outer circumferential portion of the bearing portion152, as shown in FIG. 1. When the optical pickup 111 is moved to theinnermost part of the recording area of the optical disc, the operatingportion 154 is abutted against the operating protrusion 156 and rotatesthe bearing portion 152 in the direction of rotation of the rotary shaft147.

[0016] The rotary shaft 147 is provided upright on the supporting base123 and is rotatably inserted in the shaft hole of the bearing portion152 of the opening/closing member 146. The tension coil spring 148 hasits one end retained by a retaining piece 158 provided on the supportingbase 123 and has its other end retained by a retaining piece 159situated near the bearing portion 152 of the opening/closing member 146,as shown in FIG. 1. The tension coil spring 148 energizes the rackportion 133 of the supporting base 123 and the rack portion 138 of theslide member 126 in the direction for offsetting the backlash withrespect to the driving gear 128, and is precisely moved to thesupporting base 123 and the slide member 126 by the driving gear 128.That is in the optical pickup device, since the rack portion 133 of thesupporting base 123 and the rack portion 138 of the slide member 126 areenergized by the compression coil spring 127 and thus meshed with thedriving gear 128, the optical pickup 111 can be moved with highprecision.

[0017] On the chassis 113, a disc rotational driving mechanism forrotationally driving the optical disc is provided. The disc rotationaldriving mechanism has a disc table 160 on which the optical disc is set,and a spindle motor (not shown) for rotationally driving the disc table160, as shown in FIG. 4.

[0018] In the optical pickup device constituted as described above, whenreproducing information from the optical disc, the supporting base 123is moved along the supporting shaft 124 and the guide portion 125 by themoving mechanism 112, and the optical pickup 111 is moved in the radialdirection of the optical disc.

[0019] In the optical pickup device, as shown in FIG. 5, when theoptical pickup 111 is moved in the radial direction of the optical discto the innermost part of the recording area of the optical disc, theoperating portion 154 of the opening/closing member 146 is abuttedagainst the operating portion 156 on the chassis 113 and the opticalpickup 111 is moved further by a predetermined quantity, thus rotatingthe opening/closing member 146 in the direction of an arrow c2 againstthe energizing force of the tension coil spring 148. In the opticalpickup device, when the optical pickup 111 is moved to the innermostcircle of the optical disc, the opening/closing member 146 is rotated tothe closing position to close the aperture 121 of the cover member 120,thus preventing attachment of dust and particles to the facing surfaceof the objective lens 118, as shown in FIG. 5.

[0020] In the optical pickup device, when the optical pickup 111 ismoved into a TOC (table of contents) area on the inner side of therecording area, the opening/closing member 146 is rotated to the openingposition and the facing surface of the objective lens 118 of the opticalpickup 111 is exposed to the optical disc, thus enabling reproduction ofinformation from the optical disc. The optical pickup 111 reproducesinformation from the optical disc while the opening/closing member 146is situated to the opening position, as shown in FIG. 4.

[0021] Since the opening/closing mechanism 145 for causing theopening/closing member 146 to carry out the opening/closing operationhas the rotary shaft 147 and the tension coil spring 148, theabove-described conventional optical pickup device has problems that themanufacturing cost is high, that the assembly work is troublesome, andthat assembly failure tends to occur.

[0022] In the conventional optical pickup device, since theopening/closing member 146 is rotatably provided via the rotary shaft147, the lever ratio is related to the quantity of rotation near thebearing portion 152 and the quantity of rotation of the opening/closingportion 151.

[0023] In the conventional optical pickup device, since the ratio of thequantity of movement of the optical pickup 111 moved when rotating theopening/closing member 146 to the quantity of rotation of theopening/closing member 146 is large, it is difficult to control theopening/closing operation of the opening/closing member 146 inaccordance with the movement of the optical pickup 111 by a controlcircuit or the like.

[0024] Therefore, the conventional optical pickup device has a problemthat the irregularity of the rotating position of the opening/closingmember 146 prevents complete closure of the aperture 121 of the covermember 120. To restrain the irregularity of the opening/closingoperation of the opening/closing member 146, the opening/closingmechanism 145 must increase the precision of each of its component partsand therefore the manufacturing cost must be increased.

[0025] In the conventional optical pickup device, the unevenness in theassembly precision or the like of the opening/closing mechanism 145causes slight unevenness in the slide resistance between the guideportion 153 of the opening/closing member 146 and the guide piece 155 ofthe cover member 120. Since the slide resistance is amplified by thelever ratio, the opening/closing member 146 cannot carry out theopening/closing operation.

DISCLOSURE OF THE INVENTION

[0026] Thus, it is an object of the present invention to provide anoptical pickup device which enables improvement in the reliability ofthe opening/closing operation of the opening/closing member forpreventing attachment of dust and particles to the objective lens of theoptical pickup, realization of simplification of the overall structureand reduction in manufacturing cost, and recording and/or reproducingdevice having this optical pickup device.

[0027] A recording and/or reproducing device according to the presentinvention is a device using an optical disc as a recording medium. Thedevice comprises: an optical pickup having an objective lens andprovided to be movable in the radial direction of an optical disc; afirst rack portion provided on the optical pickup; a slide member havingan opening/closing portion for opening/closing a facing surface of theobjective lens to the optical disc, and a second rack portion providedto be slidable on the first rack portion; and a driving mechanism havinga driving gear which meshes with the first rack portion and the secondrack portion. In this device, when the first and second rack portionsare driven by the driving gear and the optical pickup is thus moved to apredetermined position, the meshing state of the first rack portion withthe driving gear is canceled and the second rack portion is driven bythe driving gear to move the slide member, thereby moving theopening/closing portion from a position for opening the facing surfaceside of the objective lens to a position for closing the facing surfaceside.

[0028] This device further comprises a detecting section for detectingthat the optical pickup has reached a predetermined position on theinner circle side of the optical disc. The detecting section is operatedby the optical pickup when the optical pickup reaches at least aposition in a table-of-contents area of the optical disc.

[0029] The device according to the present invention further comprises acontrol section for driving a driving motor for a predetermined timeperiod on the basis of a detection output from the detecting section. Asthe driving motor is driven for a predetermined time period, the opticalpickup is moved further toward the inner circle side of the opticaldisc.

[0030] In the recording and/or reproducing device according to thepresent invention, when the first and second rack portions are driven bythe driving gear and the optical pickup is thus moved to a predeterminedposition, the meshing state of the first rack portion with the drivinggear is canceled and the second rack portion is driven by the drivinggear to move the slide member, thereby moving the opening/closingportion from a position for opening the facing surface side of theobjective lens to a position for closing the facing surface side andcausing the opening/closing portion to close the facing surface side ina standby state.

[0031] An optical pickup device according to the present inventioncomprises: an optical pickup section having an objective lens andprovided to be movable along a guide portion; a first rack portionprovided on the optical pickup section; a slide member having anopening/closing portion for opening/closing a facing surface of theobjective lens to an optical disc, and a second rack portion provided tobe slidable on the first rack portion; and a driving mechanism having adriving gear which meshes with the first rack portion and the secondrack portion. In this optical pickup device, when the first and secondrack portions are driven by the driving gear and the optical pickupsection is thus moved to a predetermined position, the meshing state ofthe first rack portion with the driving gear is canceled and the secondrack portion is driven by the driving gear to move the slide member,thereby moving the opening/closing portion from a position for openingthe facing surface side of the objective lens to a position for closingthe facing surface side.

[0032] In this optical pickup device, at least one protrusion isprovided on the slide member, and an abutment portion to be abuttedagainst the protrusion is provided on the optical pickup section. As thesecond rack portion is moved in a direction such that theopening/closing portion opens the facing surface side so as to abut theprotrusion against the abutment portion, the first rack portion ismeshed with the driving gear.

[0033] The optical pickup device further comprises an elastic membertensioned between the first rack portion and the second rack portion.

[0034] The optical pickup section further has a cover which has anaperture formed therein at a position facing the objective lens andwhich is adapted for at least covering the objective lens. Theopening/closing portion moves on the cover between the position foropening the facing surface and the position for closing the facingsurface, thus opening/closing the aperture.

[0035] The optical pickup device further has a guide portion for guidingthe movement of the optical pickup section in the radial direction ofthe optical disc. The guide portion has a supporting shaft for guidingthe optical pickup section, a reference portion abutted at least at twopositions of an outer circumferential portion of the supporting shaftfor positioning the supporting shaft, an engagement portion engaged withthe outer circumferential portion of the supporting shaft, and anelastic displacement portion formed integrally with the engagementportion for energizing the engagement portion in the radial direction ofthe supporting shaft. The elastic displacement portion is bent from adirection substantially parallel to the axial direction of thesupporting shaft to a direction substantially orthogonal to the axialdirection of the supporting shaft, thereby energizing the engagementportion in the radial direction of the supporting shaft.

[0036] The other objects and advantages of the present invention will beclarified further from the specific description of the embodiment withreference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0037]FIG. 1 is an exploded perspective view for explaining aconventional optical pickup device.

[0038]FIG. 2 is a perspective view for explaining a supporting baseprovided in the conventional optical pickup device.

[0039]FIG. 3 is a plan view for explaining a rack portion of thesupporting base and a rack portion of a slide member provided in theconventional optical pickup device.

[0040]FIG. 4 is a plan view for explaining the state in which anopening/closing member of an opening/closing mechanism provided in theconventional optical pickup mechanism is opened.

[0041]FIG. 5 is a plan view for explaining the state in which theopening/closing member of the opening/closing mechanism is closed.

[0042]FIG. 6 is a plan view showing essential parts of a disc drivedevice in which an optical pickup device according to the presentinvention is provided.

[0043]FIG. 7 is an exploded perspective view showing an optical pickupdevice.

[0044]FIG. 8 is a plan view showing an optical pickup device using ashaft fixing mechanism according to the present invention.

[0045]FIG. 9 is a perspective view showing the shaft fixing mechanism.

[0046]FIG. 10 is a side view showing an engagement portion of a fixingpiece of the shaft fixing mechanism.

[0047]FIG. 11 is a side view showing the state in which the engagementportion of the fixing piece is engaged with a supporting shaft.

[0048]FIG. 12 is a perspective view for explaining an optical pickupdevice.

[0049]FIG. 13 is a plan view for explaining a rack portion of asupporting base and a rack portion of a slide member provided in theoptical pickup device.

[0050]FIG. 14 is a plan view for explaining one cog of the rack portionof the supporting base.

[0051]FIG. 15 is schematic view for explaining the state in which anopening/closing plate of the optical pickup device is moved to a closingposition.

[0052]FIG. 16 is a schematic view for explaining the state in which theopening/closing plate is moved to an opening position.

[0053]FIG. 17 is a schematic view for explaining the state in which anobjective lens of the optical pickup device is moved to a TOC area of anoptical disc.

[0054]FIG. 18 is a schematic view for explaining the state in which theobjective lens of the optical pickup device is moved to a recording areaof the optical disc.

[0055]FIG. 19 is a flowchart for explaining the outline of theopening/closing operation of the opening/closing plate.

[0056]FIG. 20 is a view for explaining the operation timing of adetection switch provided in the optical pickup device.

[0057]FIG. 21 is a view for explaining the relation between theopening/closing operation of the opening/closing plate and the positionof the optical pickup.

BEST MODE FOR CARRYING OUT THE INVENTION

[0058] An optical pickup device to which the present invention isapplied and a disc drive device using this optical pickup device willnow be described with reference to the drawings.

[0059] The disc drive device using the optical pickup device accordingto the present invention has an optical pickup device 1 for recording orreproducing information to or from an optical disc, and a disc drivingmechanism 2 for rotationally driving an optical disc, as shown in FIG.6.

[0060] An optical disc loaded on the disc drive device according to thepresent invention may be exemplified by a CD (compact disc) on whichinformation is recorded. On the inner circle side and the outer circleside of the recording area of the optical disc in which information isrecorded, a lead-in area and a lead-out area are provided, respectively.In the lead-in area, a TOC (table of contents), area is provided inwhich, for example, the index and physical address of the recordedinformation are recorded.

[0061] The optical pickup device 1 according to the present inventionhas an optical pickup section 11 having an objective lens 14, a movingmechanism 12 for moving the optical pickup section 11 in the directionsof arrows a1 and a2 parallel to the radial direction of the opticaldisc, and a chassis 13 for movably supporting the optical pickup section11 and also supporting the moving mechanism 12, as shown in FIG. 6.

[0062] The optical pickup section 11 is movably provided in an aperture16 for movement provided in the chassis 13, as shown in FIGS. 6 and 7.The optical pickup section 11 has an optical system having the objectivelens 14, an electromagnetic driving section (not shown) for driving anddisplacing the objective lens 14 in the focusing direction parallel tothe optical axis of the objective lens and in the tracking directionorthogonal to the optical axis, and a cover member 18 for covering theelectromagnetic driving section.

[0063] The electromagnetic driving section has a lens holder for holdingthe objective lens 14, a supporting mechanism for supporting the lensholder displaceably in the focusing direction and the trackingdirection, and an electromagnetic circuit section for driving anddisplacing the objective lens 14 by an electromagnetic force, though notshown.

[0064] In the optical pickup section 11, the optical system has a laserdiode as a light source for emitting a laser beam, a group of lensesconstituting the optical system, and a light receiving section forreceiving a reflected light from the optical disc, though not shown. Thelaser beam emitted from the laser diode is converged by the objectivelens 14 and thus cast onto the recording layer of the optical disc. Thelaser beam is reflected by the recording layer of the optical disc,becomes incident on the optical pickup section 11 via the objective lens14, and is received by the light receiving section.

[0065] The cover member 18 is made of, for example, an ABS resin or thelike, and is formed in a substantially box-like shape having an uppersurface substantially parallel to the recording surface of the opticaldisc. As shown in FIGS. 6 and 7, an aperture 20 for exposing theobjective lens 14 to the recording surface of the optical disc isprovided substantially at the center of the upper surface of the covermember 18. This aperture 20 is formed in a substantially elliptic shapehaving a longer side in the radial direction of the optical disc.

[0066] The moving mechanism 12 has a supporting base 21 for supportingthe optical pickup device, a supporting shaft 22 for supporting thesupporting base 21 movably in the radial direction of the optical disc,a guide portion 23 for movably guiding the supporting base 21, a slidemember 24 for moving the supporting base 21, a tension coil spring 25for energizing the slide member 24 in the axial direction of thesupporting shaft 22 with respect to the supporting base 21, a drivinggear 26 for driving the slide member 24, a group of gears (not shown)for rotationally driving the driving gear 26, and a driving motor 28 forrotationally driving the driving gear 26 via the group of gears, asshown in FIG. 7.

[0067] The optical pickup device 1 according to the present inventionhas a shaft fixing mechanism 80 for positioning the supporting shaft 22to the chassis 13.

[0068] The shaft fixing mechanism 80 is provided on both ends of thesupporting shaft 22, and includes the supporting shaft 22, the chassis13, a positioning piece 81 for positioning the supporting shaft 22 tothe chassis 13, and a fixing piece 82 for fixing the supporting shaft 22to the chassis 13, as shown in FIGS. 8 and 9. The supporting shaft 22and the chassis 13 are made of a metal material.

[0069] The positioning piece 81 is formed integrally with the chassis 13by cutting and raising a part of the chassis 13 to be substantiallyorthogonal to the major surface of the chassis, as shown in FIG. 9. Thefixing piece 82 has an engagement portion 85 engaged with an outercircumferential portion of the supporting shaft 22, an elasticdisplacement portion 86 for energizing the engagement portion 85 topress in the radial direction of the supporting shaft 22, and a proximalend portion 87 integrally formed with the chassis 13.

[0070] The engagement portion 85 is formed with a size which allows easybending with respect to the proximal end portion 87. The elasticdisplacement portion 86 is formed with a narrower width than those ofthe engagement portion 85 and the proximal end portion 87, thus securingpredetermined elasticity, as shown in FIG. 9.

[0071] On the major surface of the chassis 13, regulating protrusions89, 89 which are abutted against both ends of the supporting shaft 22 soas to regulate the displacement of the supporting shaft 22 in the axialdirection are integrally provided at both ends of the supporting shaft22, as shown in FIG. 8.

[0072] In the fixing piece 82, as the elastic displacement portion 86 isbent in advance by pressing, the engagement portion 85 is madeorthogonal to the proximal end portion 87 and is thus made substantiallyparallel to the axial direction of the supporting shaft 22, as shown inFIGS. 8 and 9. When the engagement portion 85 is made substantiallyparallel to the proximal end portion 87 by bending the elasticdisplacement portion 86 and is thus made substantially orthogonal to theaxial direction of the supporting shaft 22, a slope 88 is engaged withthe outer circumferential portion of the supporting shaft 22, as shownin FIG. 11.

[0073] A shaft fixing method for positioning and fixing the supportingshaft 22 to the chassis 13 by using the shaft fixing mechanism 80constituted as described above will now be described with reference tothe drawings.

[0074] The supporting shaft 22 has its outer circumferential portionabutted against a reference surface 83 of the positioning piece 81 and areference surface 84 of the chassis 13, and is thus positioned withrespect to the chassis 13.

[0075] The engagement portion 85 of the fixing piece 82, bent in thedirection substantially orthogonal to the proximal end portion 87, ridesover the outer circumferential portion of the supporting shaft 22, andthe slope 88 of the engagement portion 85 slides on the outercircumferential portion of the supporting shaft 22. Thus, the engagementportion 85 is made substantially parallel to the proximal end portion 87and the elastic displacement portion 86 is partly bent to make theengagement portion 85 substantially orthogonal to the axial direction ofthe supporting shaft 22.

[0076] When the engagement portion 85 of the fixing piece 82 is bent tobe substantially orthogonal to the axial direction of the supportingshaft 22, the engagement portion 85 is engaged with the outercircumferential portion of the supporting shaft 22 and the engagementportion 85 is energized to be pressed in the radial direction of thesupporting shaft 22 by the elastic force of the elastic displacementportion 86.

[0077] Specifically, as shown in FIG. 10, since the engagement portion85 has an area S which overlaps the cross section of the supportingshaft 22 when the engagement portion 85 is substantially parallel to theproximal end portion 87, the elastic displacement portion 86 iselastically displaced with respect to the outer circumferential portionof the supporting shaft 22 in accordance with the area S. Therefore, theengagement portion 85 presses and securely fixes the supporting shaft 22by a predetermined pressing force in the radial direction of thesupporting shaft 22 due to the elastic force of the elastic displacementportion 86 which is elastically displaced.

[0078] In the shaft fixing mechanism 80 as described above, since theengagement portion 85 of the fixing piece 82 is formed integrally withthe chassis 13, no looseness due to any vibration or shock is generatedin the engagement portion 85 for fixing the supporting shaft 22 and thesupporting shaft 22 can be securely fixed.

[0079] In the shaft fixing mechanism 80, since the fixing piece 82 isformed integrally with the chassis 13, the number of components and themanufacturing cost can be reduced.

[0080] The supporting base 21 has the optical pickup section 11 arrangedon its major surface, and has a bearing portion 31 in which thesupporting shaft 22 is movably inserted, and a pair of guide pieces 32,32 movably engaged with the guide portion 23, as shown in FIG. 12. Atone lateral edge of the supporting base 21, a rack portion 33 isintegrally formed which is meshed with and moved by the driving gear 26,as shown in FIG. 7.

[0081] The rack portion 33 is formed parallel to the axial direction ofthe supporting shaft 22, as shown in FIG. 7. On the rack portion 33,engagement pawls 35, 36 movably engaged with the slide member 24 and aretaining piece 37 for retaining one end of the tension coil spring 25are integrally formed. In the rack portion 33, a cog 38 at the terminalend on the outer circumferential side of the optical disc is formed in asubstantially triangular shape with a half thickness of the other cogs39, as shown in FIGS. 13 and 14, and therefore is easily detached fromthe driving gear 26 to cancel the meshing state of the rack portion 31with the supporting base 21.

[0082] On the supporting base 21, at a position corresponding to theinner circle side of the optical disc, a inner-side stopper piece 41 forregulating the movement of the supporting base 21 in the direction ofthe arrow a1 is integrally formed to protrude parallel to the, directionof the movement of the supporting base 21, as shown in FIG. 12. On thechassis 13, at one lateral edge on the inner circle side of the aperture16 for movement, a regulating recess portion 42 is cut out and formed towhich the inner-side stopper piece 41 of the supporting base 21 isabutted.

[0083] On the supporting base 21, at a position corresponding to theouter circle side of the optical disc, an outer-side stopper piece 43for regulating the movement of the supporting base 21 in the directionof the arrow a2 is integrally formed to protrude parallel to thedirection of the movement of the supporting base 21, as shown in FIG.12. On chassis 13, at one lateral edge on the outer circle side of theaperture 16 for movement, a regulating recess portion 44 is cut out andformed to which the outer-side stopper piece 43 of the supporting base21 is abutted.

[0084] As shown in FIGS. 6 and 7, the supporting shaft 22 has its bothends fixed on the chassis 13 by fixing portions (not shown), with itsaxial direction arranged parallel to the radial direction of the opticaldisc over the movement aperture 16 of the chassis 13.

[0085] The guide portion 23 is formed parallel to the axial direction ofthe supporting shaft 22 along one lateral edge of the movement aperture16 of the chassis 13, as shown in FIGS. 7 and 12. The guide pieces 32,32 of the supporting base 21 stand face to face from above and below theguide portion 23 and the supporting base 21 movably engaged with guideportion 23, thus regulating the movement of the supporting base 21 inthe direction of axial rotation of the supporting shaft 22.

[0086] The slide member 24 has a rack portion 46 formed parallel to theaxial direction of the supporting shaft 22, as shown in FIG. 7. Theslide member 24 is mounted on the supporting base 21 so that the rackportion 46 is coincident with the rack portion 33 of the supporting base21. On the slide member 24, engagement grooves 48, 49 are formed whichare engaged with the engagement pawls 35, 36 of the rack portion 33 ofthe supporting base 21 in such a manner as to enable movement parallelto the axial direction of the supporting shaft 22.

[0087] On the slide member 24, regulating pins 50, 50 for regulating therelative position to the rack portion 33 are integrally formed toprotrude, as shown in FIGS. 7 and 13. As the regulating pins 50, 50 areabutted against the one engagement pawl 36 of the engagement pawls 35,36 provided on the rack portion 33 of the supporting base 21, therelative position of the slide member 24 to the rack portion 33 isregulated.

[0088] On the slide member 24, a guide piece 52 movably engaged with thedriving gear 26 is integrally formed to protrude along the rack portion46. On the slide member 24, a retaining piece 53 for retaining thetension coil spring 25 is integrally formed.

[0089] The tension coil spring 25 has its one end retained by theretaining piece 37 of the rack portion 33 of the supporting base 21, andhas its other end retained by the retaining piece 53 of the slide member24, as shown in FIG. 7. Therefore, the tension coil spring 25 energizes,by its elastic force, the slide member 24 in the direction of the arrowa2 parallel to the axial direction of the supporting shaft 22 withrespect to the rack portion 33 of the supporting base 21.

[0090] The driving gear 26 has a gear portion 55 meshed with the rackportion 33 of the supporting base 21 and the rack portion 46 of theslide member 24, as shown in FIG. 7. At the distal end of the drivinggear 26, a guide groove 56 is formed with which the guide piece 52 ofthe slide member 24 is movably engaged, as shown in FIG. 7. The drivinggear 26, and the group of gears, not shown, are provided on the chassis13 so as to be rotatable via the supporting shaft 22. The driving motor28 is provided on the chassis 13. The driving force from the drivingmotor 28 is transferred to the driving gear 26 via the group of gears,not shown.

[0091] The moving mechanism 12 has an opening/closing plate 58 which isenabled to move between a closing position for covering a facingsurface, which faces the optical disc, of the objective lens 14 of theoptical pickup section 11, and an opening position for opening thefacing surface of the objective lens 14 so as to expose it to theoptical disc, as shown in FIGS. 6 and 7.

[0092] The opening/closing plate 58 is formed integrally with the slidemember 24 by using a resin material such as POM (polyoxymethylene) orthe like, as shown in FIG. 7. The opening/closing plate 58 is formed ina substantially rectangular shape having an area large enough to closethe aperture 20 of the cover member 18. The opening/closing plate 58 isformed to protrude from the slide member 24 via a pair of elastic linearconnection pieces 59, 59, and is energized toward the upper surface ofthe cover member 18 by the elastic force of the connection pieces 59,59, as shown in FIG. 7.

[0093] The moving mechanism 12 has a detection mechanism 60 fordetecting that the optical pickup section 11 is moved into the TOC areaof the optical disc or the inner circle side of the TOC area, as shownin FIGS. 7 and 12. The detection mechanism 60 is constituted by adetection piece 61 provided on the supporting base 21, and a detectionswitch 62 operated by the detection piece 61.

[0094] The detection piece 61 is formed integrally with the supportingbase 21 by protecting a part of the supporting base 21 on the bottomside of the supporting base in the direction substantially orthogonal tothe direction of the movement of the optical pickup section 11.

[0095] The detection switch 62 is provided on a circuit board, notshown, mounted on the chassis 13. More precisely, the detection switch62 is arranged at a position such that it is abutted against thedetection piece 61 when the objective lens 14 of the optical pickupsection 11 on the circuit board, not shown, is moved substantially tothe center in the radial direction of the TOC area of the optical disc.As will be described later, on the circuit board, not shown, there isprovided a controller 71 having a timer circuit 72 for moving theoptical pickup section 11 for a predetermined time period after theoptical pickup section 11 is detected by the detection switch 62 asshown in FIG. 19. A driving circuit 73 for the driving motor 28 is alsoprovided on the circuit board.

[0096] The driving motor 28 is driven for a predetermined time period bythe timer circuit 72 of the controller 71, and thus moves the slidemember 24 by a predetermined quantity with respect to the rack portion33 of the supporting base 21, thereby moving the opening/closing plate58 to the closing position for closing the aperture 20 of the covermember 18.

[0097] The disc rotational driving mechanism 2 has a disc table 65 onwhich the optical disc is set, and a spindle motor (not shown) forrotationally driving the disc table 65, as shown in FIG. 6. The spindlemotor, not shown, is fixed to the chassis 13 and is drive-controlled bythe driving circuit provided on the above-described circuit board, notshown, so that the optical disc rotates at a constant linear velocity.

[0098] The opening/closing operation of tie opening/closing plate 58accompanied by the movement of the optical pickup section 11, in theoptical pickup device 1 of the disc drive device constituted asdescribed above, will now be described with reference to the drawings.

[0099] First, in the optical pickup device 1 in the standby state, theoptical pickup section 11 is situated on the inner circle side of theTOC area of the optical disc. As shown in FIG. 15, the aperture 20 ofthe cover member 18 is closed by the opening/closing plate 58 and thefacing surface of the objective lens 14 to the optical disc is thuscovered by the opening/closing plate 58. Therefore, in the opticalpickup device 1 in the standby state, attachment of dust and particlesto the facing surface of the objective lens 14 to the optical disc isprevented by the opening/closing plate 58. In the optical pickup device1 in this standby state, the meshing state between the rack portion 33of the supporting base 21 and the driving gear 26 is canceled and therack portion 46 of the slide member 24 having the opening/closing plate58 provided thereon is meshed with the driving gear 26, as shown in FIG.15. Hereinafter this state is called state S₄.

[0100] Next, in the optical pickup device 1, when reproduction of theoptical disc is started, the motor 28 is driven on the basis of adriving signal from the driving circuit section 73 controlled by thecontroller 71 and the driving gear 26 is thus driven, as shown in FIG.16. The slide member 24 having the rack portion 46 meshed with thedriving gear 26 is moved in the direction of the arrow a2 by the drivinggear 26. As a result, the opening/closing plate 58 is moved in thedirection of the arrow a2 to the opening position for opening theaperture 20 of the cover member 18 and for exposing the facing surfaceof the objective lens 14 to the optical disc. As shown in FIG. 16, inthe optical pickup device 1, as the slide member 24 is moved in thedirection of the arrow a2 by the driving gear 26, the regulating pins50, 50 of the slide member 24 are abutted against the engagement pawl 36of the rack portion 33 of the supporting base 21. Hereinafter, thisstate is called state S₃.

[0101] In the optical pickup device 1, as the regulating pins 50, 50 areabutted against the engagement pawl 36, the energizing force of thetension coil spring 25 acts on the supporting base 21 and the supportingbase 21 is moved in the direction of the arrow a2. Therefore, in theoptical pickup device 1, the rack portion 33 of the supporting base 21is meshed with the driving gear 26, and the cogs of the rack portion 33of the supporting base 21 and the cogs of the rack portion 46 of theslide member 24 become coincident with each other and meshed with thedriving gear 26, as shown in FIG. 17. In this case, the supporting base21 is displaced by a small distance d in the direction of the arrow a2because of the meshing of the rack portion 33 with the driving gear 26.Therefore, in the moving mechanism 12, the engagement pawl 36 is movedaway by the small distance d from the regulating pins 50, 50, along withthe displacement of the supporting base 21 by the small distance d inthe direction of the arrow a2, as shown in FIG. 17. In the movingmechanism 12, since the regulating pins 50, 50 and the engagement pawl36 are brought away from each other, the energizing force of the tensioncoil spring 25 acts to offset the backlash of the rack portion 33 of thesupporting base 21 and the rack portion 46 of the slide member 24 withrespect to the driving gear 26, as shown in FIG. 17. Hereinafter, thisstate is called state S₂.

[0102] In the optical pickup device 1, as shown in FIG. 18, since thebacklash is offset by the energizing force of the tension coil spring 25in the reproducing state in which the optical pickup section 11 isreading out information from the recording area of the optical disc, themoving mechanism 12 can precisely move the optical pickup section 11 inthe directions of the arrows a1 and a2 and information recorded on theoptical disc can be satisfactorily read out by the optical pickupsection 11. Hereinafter, this state is called state S₁.

[0103] When the stop of reproduction of the optical disc is set byoperating a stop button, not shown, of the drive device, the opticalpickup section 11 of the optical pickup device 1 is moved in thedirection of the arrow a1 toward the inner circle side of the opticaldisc under the control of the controller 71, as shown in FIG. 17. If theoptical pickup section 11 is moved into the TOC area of the optical discor to a position on the inner side than the TOC area, the detectionpiece 61 of the supporting base 21 is abutted against the detectionswitch 62, thus operating the detection switch 62. The detection switch62 is set in the ON-state and it is detected that the optical pickupsection 11 is moved into the TOC area or to a position on the inner sidethan the TOC area.

[0104] When the detection switch 62 is set in the ON-state as shown inFIG. 17, a detection signal from the detection switch 62 is supplied tothe controller 71, as shown in FIG. 19. This controller 71 controls thedriving circuit 73 so that the driving circuit 73 outputs a drivingsignal for rotationally driving the driving motor 28, by a predeterminedtime period timed by the timer circuit 72. That is, the moving mechanism12 moves the optical pickup section 11 in the direction of the arrow a1by using the driving motor 28, by a time period preset by the timercircuit 72, as shown in FIG. 21.

[0105] The detection switch 62 is operated and set in the ON-state bythe detection piece 61 of the supporting base 21 when the optical pickupsection 11 is situated substantially at the center of the TOC area ofthe optical disc, as shown in FIGS. 20 and 21.

[0106] As shown in FIGS. 16 and 21, when the optical pickup section 11is moved further in the direction of the arrow a1 and the optical pickupdevice 1 is in the state S₃ shown in FIG. 16, the inner-side stopperpiece 41 of the supporting base 21 is abutted against the regulatingrecess portion 42 and the movement of the supporting base 21 isregulated, thus stopping the movement of the optical pickup section 11.As shown in FIGS. 16 and 19, in the moving mechanism 12, since themovement of the supporting base 21 is regulated, the cog 38 of the rackportion 33 of the supporting base 21 is detached from the driving gear26 and the meshing state of the rack portion 33 with the driving gear 26is canceled.

[0107] In the optical pickup device 1, as shown in FIGS. 15 and 21, thedriving motor 28 is driven by a predetermined time period preset by thetimer circuit 72 after the movement of the supporting base 21 isregulated. As a result, only the slide member 24 is moved in thedirection of the arrow a1 by the driving gear 26 against the elasticforce of the tension coil spring 25. Therefore, in the moving mechanism12, as shown in FIGS. 15 and 21, the slide member 24 is moved in thedirection of the arrow a1 relatively to the supporting base 21, and theopening/closing plate 58 provided on the slide member 24 is moved in thedirection of the arrow a1 to the closing position for closing theaperture 20 of the cover member 18 and for covering the facing surfaceof the objective lens 14 of the optical pickup section 11 to the opticaldisc.

[0108] As is described above, in the optical pickup device 1 accordingto the present invention, since the opening/closing plate 58 is securelysituated at the opening position for opening the aperture 20 when theobjective lens 14 of the optical pickup section 11 is situated in theTOC area of the optical disc, TOC data recorded in the TOC area of theoptical disc can be read out satisfactorily.

[0109] As is described above, in the optical pickup device 1 provided inthe disc drive device, since the opening/closing operation of theopening/closing plate 58 is not affected by the lever ratio as in theconventional opening/closing mechanism, it is possible to preciselycontrol the operation for opening/closing the aperture 20 by theopening/closing plate 58. Thus, it is possible to improve thereliability of the opening/closing operation and to precisely controlthe operation.

[0110] Therefore, with the optical pickup device 1 according to thepresent invention, since the aperture 20 of the cover member 18 can besecurely closed by the opening/closing plate 58, attachment of dust andparticles to the objective lens 14 can be prevented satisfactorily.

[0111] In the optical pickup device 1 provided in the disc drive device,since the energizing force of the tension coil spring 25 is used foroffsetting the backlash and for energizing the opening/closing plate 58in the opening direction, the rotary shaft 147 and the tension coilspring 148 of the above-described conventional opening/closing mechanism145 are not necessary. Therefore, the number of components is reducedand the structure is simplified, thus enabling reduction inmanufacturing cost.

[0112] As the structure is simplified, the assembly work for the discdrive device and the optical pickup device can be simplified. Therefore,improvement in workability, reduction in assembly failure andimprovement in yield can be realized.

[0113] Although the above-described disc drive device is constituted toreproduce information from an optical disc, the disc drive device mayalso be constituted to record information to a write-once type opticaldisc which enables additional writing of information or a rewritableoptical disc to which information can be rewritten. As a matter ofcourse, the disc drive device may also be constituted torecord/reproduce information to/from other optical discs such as amagneto-optical disc or the like, by providing a magnetic head mechanismfor recording information at a position facing the optical pickupdevice.

[0114] Industrial Applicability

[0115] As is described above, with the optical pickup device accordingto the present invention and the recording and/or reproducing deviceusing this optical pickup device, it is possible to improve thereliability of the opening/closing operation of the opening/closingmember and to securely prevent attachment of dust and particles to thefacing surface of the objective lens. Moreover, with the optical pickupdevice and the recording and/or reproducing device, simplification ofthe overall structure and reduction in manufacturing cost can berealized.

1. A recording and/or reproducing device comprising: an optical pickuphaving an objective lens and provided to be movable in the radialdirection of an optical disc; a first rack portion provided on theoptical pickup; a slide member having an opening/closing portion foropening/closing a facing surface of the objective lens to the opticaldisc, and a second rack portion provided to be slidable on the firstrack portion; and a driving mechanism having a driving gear which mesheswith the first rack portion and the second rack portion; wherein whenthe first and second rack portions are driven by the driving gear andthe optical pickup is thus moved to a predetermined position, themeshing state of the first rack portion with the driving gear iscanceled and the second rack portion is driven by the driving gear tomove the slide member, thereby moving the opening/closing portion from aposition for opening the facing surface side of the objective lens to aposition for closing the facing surface side.
 2. The recording and/orreproducing device as claimed in claim 1, wherein when the opticalpickup has reached a predetermined position on the inner circle side ofthe optical disc, the meshing state of the driving gear with the firstrack portion is canceled.
 3. The recording and/or reproducing device asclaimed in claim 2, further comprising a detecting section for detectingthat the optical pickup has reached a predetermined position on theinner circle side of the optical disc.
 4. The recording and/orreproducing device as claimed in claim 3, wherein the detecting sectionis operated by the optical pickup when the optical pickup has reached atleast a position in a table-of-contents area of the optical disc.
 5. Therecording and/or reproducing device as claimed in claim 3, furthercomprising a control section for driving a driving motor for apredetermined time period on the basis of a detection output from thedetecting section.
 6. The recording and/or reproducing device as claimedin claim 5, wherein as the driving motor is driven for a predeterminedtime period, the optical pickup is moved further toward the inner circleside of the optical disc.
 7. The recording and/or reproducing device asclaimed in claim 5, further comprising a regulating portion to which theoptical pickup is abutted and which is adapted for regulating themovement of the optical disc, wherein as the optical pickup is abuttedagainst the regulating portion and has its movement regulated by theregulating portion, the meshing state of the first rack portion with thedriving gear is canceled.
 8. The recording and/or reproducing device asclaimed in claim 1, wherein at least one protrusion is provided on theslide member and an abutment portion to be abutted against theprotrusion is provided on the optical pickup, and wherein as the secondrack portion is moved by the driving motor in a direction such that theopening/closing portion opens the facing surface side, thus abutting theprotrusion against the abutment portion, the first rack portion ismeshed with the driving gear.
 9. The recording and/or reproducing deviceas claimed in claim 8, further comprising an elastic member tensionedbetween the first rack portion and the second rack portion.
 10. Therecording and/or reproducing device as claimed in claim 9, wherein asthe first rack portion is meshed with the driving gear, the slide memberis slid and the protrusion and the abutment portion are moved away fromeach other.
 11. The recording and/or reproducing device as claimed inclaim 1, wherein the optical pickup further has a cover which has anaperture formed therein at a position facing the objective lens andwhich is adapted for at least covering the objective lens, and whereinthe opening/closing portion moves on the cover between the position foropening the facing surface and the position for closing the facingsurface, thereby opening/closing the aperture.
 12. The recording and/orreproducing device as claimed in claim 1, further comprising aregulating portion to which the optical pickup moved toward the innercircle of the optical disc is abutted and which is adapted forregulating the movement of the optical pickup, wherein as the opticalpickup is abutted against the regulating portion and has its movementregulated by the regulating portion, the meshing state of the first rackportion with the driving gear is canceled.
 13. The recording and/orreproducing device as claimed in claim 12, wherein the driving motor isdriven in a direction for moving the optical pickup further toward theinner circle, the second rack portion is driven and the slide member ismoved, thus moving the opening/closing portion from the position foropening the facing surface side of the objective lens to the positionfor closing the facing surface side.
 14. The recording and/orreproducing device as claimed in claim 13, wherein when the opticalpickup has been moved to at least a position in a table-of-contents areaof the optical disc, the driving motor is driven for a predeterminedtime period in the direction for moving the optical pickup furthertoward the inner circle.
 15. The recording and/or reproducing device asclaimed in claim 14, further comprising a detecting section fordetecting that the optical pickup has been moved to at least a positionin the table-of-contents area of the optical disc, and a control sectionfor driving the driving motor for a predetermined time period in thedirection for moving the optical pickup further toward the inner circle,on the basis of the detection result from the detecting section.
 16. Therecording and/or reproducing device as claimed in claim 15, wherein thecontrol section has a timer circuit for timing the predetermined timeperiod.
 17. The recording and/or reproducing device as claimed in claim12, wherein at least one protrusion is provided on the slide member andan abutment portion to be abutted against the protrusion is provided onthe optical pickup, and wherein as the second rack portion is moved bythe driving motor in a direction such that the opening/closing portionopens the facing surface side, thus abutting the protrusion against theabutment portion, the first rack portion is meshed with the drivinggear.
 18. The recording and/or reproducing device as claimed in claim17, further comprising an elastic member tensioned between the firstrack portion and the second rack portion.
 19. The recording and/orreproducing device as claimed in claim 18, wherein as the first rackportion is meshed with the driving gear, the slide member is slid andthe protrusion and the abutment portion are moved away from each other.20. An optical pickup device comprising: an optical pickup sectionhaving an objective lens and provided to be movable along a guideportion; a first rack portion provided on the optical pickup section; aslide member having an opening/closing portion for opening/closing afacing surface of the objective lens to an optical disc, and a secondrack portion provided to be slidable on the first rack portion; and adriving mechanism having a driving gear which meshes with the first rackportion and the second rack portion; wherein when the first and secondrack portions are driven by the driving gear and the optical pickupsection is thus moved to a predetermined position, the meshing state ofthe first rack portion with the driving gear is canceled and the secondrack portion is driven by the driving gear to move the slide member,thereby moving the opening/closing portion from a position for openingthe facing surface side of the objective lens to a position for closingthe facing surface side.
 21. The optical pickup device as claimed inclaim 20, wherein at least one protrusion is provided on the slidemember and an abutment portion to be abutted against the protrusion isprovided on the optical pickup section, and wherein as the second rackportion is moved by the driving motor in a direction such that theopening/closing portion opens the facing surface side, thus abutting theprotrusion against the abutment portion, the first rack portion ismeshed with the driving gear.
 22. The optical pickup device as claimedin claim 21, further comprising an elastic member tensioned between thefirst rack portion and the second rack portion.
 23. The optical pickupdevice as claimed in claim 22, wherein as the first rack portion ismeshed with the driving gear, the slide member is slid and theprotrusion and the abutment portion are moved away from each other. 24.The optical pickup device as claimed in claim 20, wherein the opticalpickup section further has a cover which has an aperture formed thereinat a position facing the objective lens and which is adapted for atleast covering the objective lens, and wherein the opening/closingportion moves on the cover between the position for opening the facingsurface and the position for closing the facing surface, thusopening/closing the aperture.
 25. The optical pickup device as claimedin claim 20, further comprising a guide portion for guiding the movementof the optical pickup section in the radial direction of the opticaldisc, wherein the guide portion has a supporting shaft for guiding theoptical pickup section, a reference portion abutted at least at twopositions of an outer circumferential portion of the supporting shaftfor positioning the supporting shaft, an engagement portion engaged withthe outer circumferential portion of the supporting shaft, and anelastic displacement portion formed integrally with the engagementportion for energizing the engagement portion in the radial direction ofthe supporting shaft.
 26. The optical pickup device as claimed in claim25, wherein the elastic displacement portion is bent from a directionsubstantially parallel to the axial direction of the supporting shaft toa direction substantially orthogonal to the axial direction of thesupporting shaft, thereby energizing the engagement portion in theradial direction of the supporting shaft.
 27. A recording and/orreproducing device comprising: an optical pickup having an objectivelens and provided to be movable in the radial direction of an opticaldisc; a first rack portion provided on the optical pickup; a slidemember having an opening/closing portion for opening/closing a facingsurface of the objective lens to the optical disc, and a second rackportion provided to be slidable on the first rack portion; and a drivingmechanism having a driving gear which meshes with the first rack portionand the second rack portion; wherein when the first and second rackportions are driven by the driving gear and the optical pickup is thusmoved to a predetermined position, the meshing state of the first rackportion with the driving gear is canceled and the second rack portion isdriven by the driving gear to move the slide member, thereby moving theopening/closing portion from a position for opening the facing surfaceside of the objective lens to a position for closing the facing surfaceside, and causing the opening/closing portion to close the facingsurface side in a standby state.
 28. The recording and/or reproducingdevice as claimed in claim 27, further comprising a regulating portionto which the optical pickup moved toward the inner circle of the opticaldisc is abutted and which is adapted for regulating the movement of theoptical pickup, wherein as the optical pickup is abutted against theregulating portion and has its movement regulated by the regulatingportion, the meshing state of the first rack portion with the drivinggear is canceled.
 29. The recording and/or reproducing device as claimedin claim 28, wherein the driving motor is driven in a direction formoving the optical pickup further toward the inner circle, the secondrack portion is driven and the slide member is moved, thus moving theopening/closing portion from the position for opening the facing surfaceside of the objective lens to the position for closing the facingsurface side.
 30. The recording and/or reproducing device as claimed inclaim 29, wherein when the optical pickup has been moved to at least aposition in a table-of-contents area of the optical disc, the drivingmotor is driven for a predetermined time period in the direction formoving the optical pickup further toward the inner circle.
 31. Therecording and/or reproducing device as claimed in claim 30, furthercomprising a detecting section for detecting that the optical pickup hasbeen moved to at least a position in the table-of-contents area of theoptical disc, and a control section for driving the driving motor for apredetermined time period in the direction for moving the optical pickupfurther toward the inner circle, on the basis of the detection resultfrom the detecting section.
 32. The recording and/or reproducing deviceas claimed in claim 31, wherein the control section has a timer circuitfor timing the predetermined time period.
 33. The recording and/orreproducing device as claimed in claim 28, wherein at least oneprotrusion is provided on the slide member and an abutment portion to beabutted against the protrusion is provided on the optical pickup, andwherein as the second rack portion is moved by the driving motor in adirection such that the opening/closing portion opens the facing surfaceside, thus abutting the protrusion against the abutment portion, thefirst rack portion is meshed with the driving gear.
 34. The recordingand/or reproducing device as claimed in claim 33, further comprising anelastic member tensioned between the first rack portion and the secondrack portion.
 35. The recording and/or reproducing device as claimed inclaim 34, wherein as the first rack portion is meshed with the drivinggear, the slide member is slid and the protrusion and the abutmentportion are moved away from each other.